Re: [stella] Light gun/pen

Subject: Re: [stella] Light gun/pen
From: emooney@xxxxxxxxxxxxxxxx (Erik Mooney)
Date: Thu, 02 Oct 1997 16:49:03 GMT
>I actually found it the other way round - knowing 6502 made
>8086 easy.  The 8086, with so many registers, feels almost
>like a high level language, especially with 16 bit registers.

I wrote a simple Galaxian-type game in C++ to help test a sprite engine a
friend is programming... it was *nice* to be able to calculate alien
movements in two lines of code instead of fifty.  The 8086 is somewhere in
the middle there... if you can figure out how to use the math coprocessor
with floating-point numbers, it does come closer to C++ than to 6502

>I wrote a fairly simple game in 8086, and managed to do all
>my routines completely with the internal registers.  I'm
>teaching someone 6510 right now, and he had used up the
>A, X, and Y registers in one routine - he didn't know what
>to do when he ran out!  So I had to introduce zero page to
>him :)  Of course, any assembly experience will help
>greatly when learning a new processor.

I did the same thing when learning the 6502.. I kept running out of
registers... and I also kept trying to subtract X from A and other stuff
that's a breeze on the 8086.

>Coding really intense video tricks on the C64 is very much
>like coding the 2600 - you're hitting video registers on
>the fly, each and every scan line at precise cycles to
>push some really cool stuff out of it - my experience
>doing that on the 64 has allowed me to get going really
>quickly on the 2600 - reading this mailing list sure
>has helped too, of course ;)

The big barrier is the framework of the whole thing - once you figure out
that you're generating the VSYNC, you're drawing each scanline one at a
time... no video memory or other PC simplifiers.  Once you get that and
know 6502 assembly, it's not hard to draw something on the screen.

Great complex graphics and good gameplay require lots of playtesting and
reviewing, though.. and that's also what this list is for :)

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